When you first signup you are greeted with this screen to get things going. Chose from the many generated funky project ids. Larger image
How to estimate cost of Google Cloud hostingUse their calculator (https://cloud.google.com/products/calculator/)
How to install software packages on linux vm on Google cloudOn a ubuntu image, you can easily install software on the system by running apt-get. This installs webserver.
This install php5
sudo apt-get install apache2
If you use centos image you will need to use yum instead of apt-get. This installs apache webserver.
sudo apt-get install php5 libapache2-mod-php5
For CentOS package instructions. Search on the web for package name that are used for apt-get with yum in search term. For example "yum mysql" if you are trying to install mysql. There is no need to install MySQL since google provides much better scalable CloudSql and it's accessible from both your compute engine and App Engine. When you delete an instance your persistent disk and boot disk are saved. Now you can start two or more instances with same boot and persistent disk. All your packages and configurations will be same on all instances.
sudo yum install httpd